1. Field of the Invention
The present invention relates to a post-processing of a recording medium which is ejected from an image forming apparatus such as a printer, a copying machine, and the like, and, in particular, to a recording medium post-processing apparatus for aligning the recording medium, a printer unit having the recording medium post-processing apparatus, a recording medium post-processing method, and a non-transitory, computer-readable medium storing a recording medium post-processing program for aligning the recording medium.
2. Description of Related Art
In recent years, there is a sheet post-processing apparatus which is provided to an image forming apparatus such that the sheet post-processing apparatus is adjacent to the image forming apparatus. The sheet post-processing apparatus aligns a plurality of sheets after the sheets are supplied from the image forming apparatus There is known a sheet post-processing apparatus which has a waiting tray that temporarily accommodates a plurality of sheets supplied from the image forming apparatus, a processing tray that is placed below the waiting tray and applies an external force to the plurality of sheets dropped from the waiting tray so as to align them, and a sheet receiving tray which is stacked with the plurality of sheets after the sheets were aligned on the processing tray and then discharged from the processing tray. The number of the sheets to be stacked on the sheet receiving tray at a time is restricted on the basis of the number of the sheets that are allowed to be accommodated in the waiting tray. Therefore, before the sheets having been aligned on the processing tray is going to be discharged to the sheet receiving tray, the sheets that had been stacked on the sheet receiving tray in advance are forced out to prevent the sheets having been aligned on the processing tray from contacting with the sheets that had been stacked on the sheet receiving tray in advance so as to disarrange them.